三沙湾表层沉积物中有机污染物的含量及风险评价

CONCENTRATIONS OF ORGANIC POLLUTANTS IN SURFACE SEDIMENTS OF THE SANSHA BAY AND RISK EVALUATION

利用气相色谱/质谱方法对三沙湾表层沉积物中多氯联苯(PCBs)、多环芳烃(PAHs)和有机氯农药(OCPs)进行测定,结果表明,PCBs、PAHs和OCPs的含量均值分别为1.28、61.76和1.18ng/g。与早期研究结果相比,PCBs含量浓度明显降低,表明其污染已得到有效控制;PAHs中高分子量组分普遍存在,通过分析菲/蒽和荧蒽/芘比值,判断其主要来源为燃料的高温燃烧;HCHs和DDTs是主要的有机氯农药污染物,二者的残留特征表明其主要来源为早期历史残留,且表层沉积物受到厌氧微生物降解。总体而言,三沙湾表层沉积物中PCBs、PAHs和OCPs的污染程度及生态风险均处于较低水平。

PCBs.PAHs and OCPs were measured by means of gas chromatography-mass spectrometry for the surface sediments collected from the Sansha Bay. The results showed that the concentrations of PCBs,PAHs and OCPs were 1.28.61.76 and 1.18 ng/g respectively. Compared with the research re- suits earlier,PCBs content decreased obviously. It means that the pollution state of PCBs had been controlled effectively. According to the ratio of P/A and F1/Py, the release from combustion of fuel was one of the most major sources of PAHs in this area. HCHs and DDTs were the main pollutants in OCPs. Source analysis suggests that HCHs and DDTs were mainly from historical residues of early us- age, and DDTs were decomposed by anaerobic microbial degradation in surface sediment. In conclu- sion,the concentration of PCBs,PAHs and OCPs suggest that the potential risk of environmental pol- lution was low in the Sansha Bay for the time being.